CVE-2023-28436
A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 and prior to prior to 1.38.2 in FreeBSD allows commands to be run with a higher privilege group ID than that specified in Tailscale SSH access rules.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Tailscale is software for using Wireguard and multi-factor authentication (MFA). A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 and prior to prior to 1.38.2 in FreeBSD allows commands to be run with a higher privilege group ID than that specified in Tailscale SSH access rules. A difference in the behavior of the FreeBSD `setgroups` system call from POSIX meant that the Tailscale client running on a FreeBSD-based operating system did not appropriately restrict groups on the host when using Tailscale SSH. When accessing a FreeBSD host over Tailscale SSH, the egid of the tailscaled process was used instead of that of the user specified in Tailscale SSH access rules. Tailscale SSH commands may have been run with a higher privilege group ID than that specified in Tailscale SSH access rules if they met all of the following criteria: the destination node was a FreeBSD device with Tailscale SSH enabled; Tailscale SSH access rules permitted access for non-root users; and a non-interactive SSH session was used. Affected users should upgrade to version 1.38.2 to remediate the issue.
- CVSS 3.1
- 8.0 HIGHCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.46% probability · 39th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-269
- Affected
- tailscale/tailscale
- Source
- security-advisories@github.com
References
- https://github.com/tailscale/tailscale/commit/d00c046b723dff6e3775d7d35f891403ac21a47dPatch
- https://github.com/tailscale/tailscale/releases/tag/v1.38.2Patch, Release Notes
- https://github.com/tailscale/tailscale/security/advisories/GHSA-vfgq-g5x8-g595Mitigation, Vendor Advisory
- https://tailscale.com/security-bulletins/#ts-2023-003Vendor Advisory
- https://github.com/tailscale/tailscale/commit/d00c046b723dff6e3775d7d35f891403ac21a47dPatch
- https://github.com/tailscale/tailscale/releases/tag/v1.38.2Patch, Release Notes
- https://github.com/tailscale/tailscale/security/advisories/GHSA-vfgq-g5x8-g595Mitigation, Vendor Advisory
- https://tailscale.com/security-bulletins/#ts-2023-003Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.